Change speed gear box



NOV. 15, A G wlLsoN CHANGE SPEED GEAR BOX Filed March 8, 1932 2 Sheets-Sheet l qa Wi/S [NVZNTOR A. (5. WILSON CHANGE SPEED GEAR BOX Nov. 15, 1932.

Filed March 8, 1932 2 Sheets-Sheet 2 EgA.

Patented Nov. 15, 1932 UNITED STATES PATENT OFFICE ANDREW GQRDON WILSONQOF WESTMINSTER, LONDON, EN GLAND cnenen SPEED GEAR BOX j Ap lication filed March 3,1932, Serial n; 597,527, and injGr'eat Britain December 8,1930.

This invention and for which I have filed an application in Great Britain December 8, 1930, relates to change speed gear boxes of the type containing a number" of constant meshi eplcyclic gear trains, any one of which may be selectively brought into action by the tightening of .a reaction. brake band around the particular gear train it is desired to bring into. action. To render the interior of such gear boxes accessible it is usual sometimes to fit them with a detachable cover plate carrying on the inside some of the selective gear which is thus brought away with the cover plate when the latter is removed.

: The present invention consists in a cover plate for a change speed gear box of the type 'hereinbefore referred to, in which such plate carries a cam shaft having a plurality of spaced cams thereon corresponding in number to the varlous eplcycllc gear trains, each cam being adapted to act upon itsown particular gear train, and means for turning the 'cam shaft so that any one of the camsmay be selectively brought into position to bring 1 2 into action a particular gear train desired,

and leaving the others out of action. The invention will now be described with reference to the accompanying drawings, in -which l Figure 1 is avertical transverse sectionof a {gear box to which the invention relates, taken on the line 1-1 of Figure 2. v i V Figure 2 is an elevation of the inside of the 0 cover of the gearbox.

' Figure 3 is a sectional view similar to Figure 1 but taken on the line 33 of Figure 2, and showing the whole of the gear box, and Figure 4 is a fragmentary view similar to Figure 2 but on a smaller scale showing a $0 difierent position of the parts.

The various epicyclic trains are arranged side by side inthe gear boxA and each has its complementary reaction drum B, one of fthese being shown complete in Figure 3.

'When it is desired to bring into operation any particular gear train, a flexible band brakefa associated with the reaction .drum Bconcerned, is tightened upon the said drum -by a toggle lever "mechanism set shown in Figures 1; and 3. For this, purpose one end bf the baa-bake is hooked at o to en a e with a correspondingly hooked finger D which isrigidly anchored at-E to the bottom of the box A. The otherend of'the band is pivoted at F toa link 0 that terminates in a toggle head '0 and is adapted to be strained upward bya-toggle lever b todraw the band brake a tightly round the drum" B. To effect this the toggle lever bis swung "a position'in the path of movement of'the 3 bar 6 and such'bar has a rocking movement about-the nose 6'. The toggle mechanism described does not form part of the present invention and the means for rockingthe buss bar form the subject matter of British Patent No. 328,660.

For the purpose ofactuating the) various struts d so that any one of themmaybe adjusted to assume a position in thepathj of the 'buss bar 6, a cam shaft fadapted to be actuated by a setting lever hereinafter re- :ferred'to, is arranged -to-extend along in front of them and carries a number of cams g, the position of each cam: being in line with one of the struts. The operating phase of each cam is displaced relativelyto that of the others, so that a determined movement of-the setting lever will have the desired selective'action on the strut concerned in order that with the operation of the buss bar re (throughthe change-or clutch; pedal) the strut concerned will bring the desired ward, the particular strut with which it is engaged will be pressed upward, and through its associated toggle mechanism will tighten the corresponding brake band of the selected gear train and bring it into action.

It will be understood during this action that all the remaining struts are" pressed forward out of engagement with the-buss bar 6 by their springs it so that these struts are out of action.

The various cams g are designed to act upon the various struts by means of spring bars or yokes is that are arranged to pivotally depend from afixed hookedbracket Z and in order to prevent two struts from si-.

mult'aneously' assuming a selective position, amultiple locking piece at is adapted to engage small projecting pieces a atthe upper ends ofthe struts d;

The locking pieces m are triangular form each pivoted at the apex m; They hang'normally in such a: way'that their sides are in contact, and t'he'outer sides 'of'jthe' two end pieces remain spaced a short distance from stops-m l The'l'ower corners of-each piece m is chamfere'd so that between each pair? of members-'m ashaped recess m is' provided, adapted to-engage with a lug a projecting from-each strut (Z and of corresponding A-shape'. With the parts in the-irnormal operative positions all'the lugs 41; are in engagement with their corresponding recesses m so that the locking'members areinthe position shown'in Figure 2, When however one of the struts has-beenselected and the buss bar 6 is swung upwards the selected strut with its lug n are raised where'- by' the lug thrusts apart the two locking pieces m between which it is engaged, the other pieces also moving aside to the extent allowed by the end stops on, as shown in Figure 4 and thereby prevent any other strut from" moving with the buss bar;

' in such gear boxes ashitherto constructed,

the cam shaft fithe spring bars or yokes k and the" hookedbra'cket Z'are designed to be ca rriedby' and between a pair of plates not showny mounted within the gear box, these parts being'made accessible from outside by a convenient hand opening closable by a cover plate. 7

The object of the present invention is to facilitate access to those parts within the gear box, as well as those devices with which they are associated.

For this purpose and acc'ordng to the present invention, the cam shaft f supported in bearings f, the spring bars or yokes 7c, the hooked brackets Z and the locking pieces m are all arranged -to be carried on or by the cover plate f so that when such isdetached andwithdrawn, all the parts carriedthereby are all brought away bodily with the: plate,

inspection and repairs'being thus facilitated not only of the parts on the cover plate but 7 of V somewhat also those parts in the gear box which he immediately behind.

As shown in the accompanying drawings, the cover plate is fitted with a suitable bearing 9 to receive a shaft 7, through which the cam shaft f is operated from the setting lever carried; on the steering wheel of a vehicle or elsewhere close on the dashboard. For this purpose, the external end of the shaft carries a short lever or crank s which is operabl'e from the selection lever (not shown) whilst. its inner end is fitted with a segment or quadrant it having skew teeth thereon. These. teeth: are 7 in: engagementv with similar teeth on a pinion a carried on the cam shaft f so that the latter is readily operable. as and when desired; Any otherforin of'rdrive may bG-HSedi to actuate the cam shaft; either by bevel gear, hydraulic geai': or." otherwisel'.

Such means for? obtaining access-to) the gearbox makes the construction easier? and facilitates fitting and repair and substantial;-

ly decreases working; costs-n To keep th' spring;- yokes k. constantly V pressed forward a coil or other spring o' is said gear trains, and toggle mechanism for actuating. said: brake: bands, and having-an aperture for renderingsaid gear" trainsmiccessible trom the exterior'of? said beat, en detachable cover plate for'closingr said apenture,a cam shaft mounted on the inner side of said cover'plate, a-plurality of spaced cams corresponding in number to: said gearrt'rains arrang'edin relatively different. phaseron-said cam shaft, sprlng members operatively' as- A sociated with: said cams, toggle mechanism actuating struts responsive to the movement of said spring members, and means; carried by said cover plate and operable from the exterior of said box forturning-the cam shaft in order to move any one of the struts: into an operative. position for the purpose described;

2. A change speed gearbox according to claim. 1, in which the spring membersare formed at their upper endswith suspension hooks and are; arranged sothat their lower ends engage the correspondingstruts;

3. Ina change speed gear box accordingto claim 1, means for preventing more'than one strut at a time being moved into an operative position. V

4.. A change speed gear" box accordingto claim 1,. in which the? cam operating means comprise a; shaft passing through the cover plate, a l'ever'on the external end' of the shaft,

a quadrant having skew teeth on the inner end of the shaft, and a pinion having similar teeth mounted on the cam shaft so that the teeth of the quadrant intermesh with those on the pinion.

In testimony whereof I have signed my name to this specification. 7 ANDREW GORDON WILSON. 

